More Immune Cells in Triple-Negative Breast Cancer May Mean Lower Recurrence Risk
Early-stage triple-negative breast cancer that has more lymphocytes, a type of immune cell, has a lower risk of coming back (recurrence), according to a study.
The research was published on April 2, 2024, by the journal JAMA. Read the abstract of “Tumor-infiltrating lymphocytes in triple-negative breast cancer.”
What are tumor-infiltrating lymphocytes?
Tumor-infiltrating lymphocytes, called TILs by doctors, are white blood cells that travel into a cancer tumor.
Lymphocytes in general help your body fight off infection and get rid of diseased cells. They constantly roam throughout the body looking for cells that shouldn’t be there, including cancer cells.
As a cancer grows, lymphocytes recognize the cells as abnormal and go into the tumor. Once inside the tumor, they’re called TILs.
Some research suggests that the more TILs in a cancer tumor, the better the outcome. But not all breast cancer tumors have high levels of TILS and doctors are trying to understand why this is.
Why do the study?
The researchers did this study to provide more information about any links between numbers of TILs in early-stage triple-negative breast cancers and lower recurrence rates in women who didn’t receive chemotherapy. They also wanted to know if higher levels of TILs were linked to better survival.
About the study
The study included 1,966 women (about 40% of them were younger than 50) diagnosed with early-stage triple-negative breast cancer who had surgery but didn’t receive chemotherapy between 1979 and 2017. Most of the women had breast cancers that were lymph node-negative and stage I and had not spread to the lymph nodes.
The women received treatment at one of 13 centers in Europe, Asia, and North America. About 60% of the women had lumpectomy followed by radiation and 40% had mastectomy.
The researchers measured the percentage of TILs in a sample of breast cancer tumor tissue from each woman:
1,300 women (66%) had tumors that were less than 30% TILs
249 women (13%) had tumors that were 30% to 49% TILs
249 women (13%) had tumors that were 50% to 74% TILs
168 women (8%) had tumors that were 75% or more TILs
Younger women were more likely to have tumors with higher levels of TILs.
Half the women were followed for less than 18 years and half were followed for a longer time.
When the data were analyzed in 2021:
55% of the women had been diagnosed with a new breast cancer or another type of cancer
48% of the women had a breast cancer recurrence
46% of the women had a metastatic recurrence
41% of the women had died
The results showed that higher TIL levels were associated with lower recurrence rates and better overall survival. Overall survival is how long a person lives whether or not the cancer recurs.
“Five years after surgery, 95% of participants …whose tumors had high TILs were alive, compared to 82% of patients whose tumors had low TILs,” co-senior author Stefan Michiels, PhD, head of the Oncostat team at the University Paris-Saclay, said in a statement. “Importantly, the breast cancer recurrence rate was significantly lower among patients whose tumors had high TILs.”
The links between more TILs and better outcomes were independent of other cancer features, including tumor size and lymph node status.
What this means for you
“These results are very exciting, as they offer the potential to design future studies where clinicians can use TILs to identify patients who may not need the intensive chemotherapy regimens that are currently recommended, and decrease the potential complications and side effects that patients experience from cancer treatment,” said Roberto Leon-Ferre, MD, first author of the paper and breast medical oncologist at the Mayo Clinic.
While measuring TIL levels isn’t standard practice, Dr. Leon-Ferre told Breastcancer.org that people diagnosed with early-stage triple-negative breast cancer can ask their treatment team if finding out TIL numbers would be appropriate and how the information might be used.
“Measuring TILs requires specific training to ensure results are done according to guidelines,” he added. “The International Immuno-Oncology Working Group has led efforts to standardize TIL assessment and train pathologists worldwide to ensure the results are reliable. A patient interested in having TILs measured in their tumor should discuss these aspects with their treatment team.”
If TIL levels are low in early-stage triple-negative disease, Dr. Leon-Ferre said the study reinforces current standards saying that chemotherapy should be strongly considered because the cancer has a higher risk of recurrence.
— Last updated on August 14, 2025 at 5:58 PM